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1968 112 HH100 Tecumseh wiring


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#1 RAJ OFFLINE  

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Posted February 01, 2016 - 01:41 PM

I am trying to figure out how to wire this tractor. It is serial number 108941. The engine was replaced with a new HH100 115255H SER 4049E  at some point. The new engine has a standalone regulator-rectifier so the original one on the tractor was bypassed. The ignition switch also was replaced at some point with a generic that did not have a provision for magneto kill and was rigged with a push button kill but never worked. I never looked into it at that time and just used the choke to stop the engine.

 

I sold the tractor to a friend a few years ago and he recently attempted to replace the ignition switch in an effort to make the engine shut off using the key switch. He ended up putting in the same generic switch, wired it back together incorrectly and melted some wiring in the process. I offered to rewire it for him as a favor. The engine does still run so I am hoping everything still works.

 

I have the tractor wiring diagram from the original JD service manual and also the Tecumseh service manual for this engine. The problem I have is the ignition switch letter codes are not in the same language between the two manuals and I need to know where to run the leads coming from the engine and the proper switch to use.

 

There is a GREEN and RED wire coming from the engine. The Tecumseh manual shows the green wire going to ignition terminal "M" and the red going to terminal "R."

 

The John Deere diagram shows a LT GREEN wire splicing into ORANGE and going to terminal "C," and a WHITE wire going to terminal "D."

 

The original ignition switch was JD # AM30771 and appears to have been replaced with AM102543.

 

Pictures to follow for reference.


Edited by RAJ, February 01, 2016 - 02:32 PM.


#2 RAJ OFFLINE  

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Posted February 01, 2016 - 01:43 PM

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#3 EricFromPa ONLINE  

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Posted February 01, 2016 - 02:38 PM

I like to keep the kill wire on an older Tecumseh Far away from Any power source.Doesn't take but 1 good spark to jump across inside the ignition switch to burn up the coil.Then it's $150-$250 for another coil or just replace the engine.


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#4 RAJ OFFLINE  

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Posted February 01, 2016 - 02:42 PM

I like to keep the kill wire on an older Tecumseh Far away from Any power source.Doesn't take but 1 good spark to jump across inside the ignition switch to burn up the coil.Then it's $150-$250 for another coil or just replace the engine.

Would you recommend staying with a push button kill and a universal ignition switch then? Which wire should go to what?

 

The year code on this engine is 4049E. Do you think it would be 49th day of 1974 or 1984?


Edited by RAJ, February 01, 2016 - 02:44 PM.


#5 EricFromPa ONLINE  

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Posted February 01, 2016 - 03:50 PM

Looked up that engine model # and it's showing the older Aluminum 1 piece SSI so I would say 1974.

 

Have you had the Blower housing off to confirm what it is?

 

I used a Single wire case grounding toggle switch on the 3 that I had to rewire.They were used in a bunch of old weed eaters and chain saws.I tried a couple of regular toggle switches both rocker style and flip type but they do not work.

 

If you grab the kill wire it will shock you a bit.Not much but you can feel it enough to let go of the wire pretty quick.They produce a bit of current and a cheap switch will ground it's self out and ark inside.Same thing happens inside of a slightly warn or even a damp or wet ignition switch.That's why so many of them go bad.

 

 

This is the same switch that I used.I had bought a couple large boxes of new old stock Homelite chain saw parts a couple years ago and there was a few of these switches.There small and work really good.

 

http://www.ebay.com/...NYAAOSwEK9T47q3    


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#6 chieffan OFFLINE  

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Posted February 01, 2016 - 04:10 PM

I suggest you forget about the JD wiring as it is not applicable with the engine change.  Been through this with several Bolens and re-wired them according to the diagram for the engine.  Like EricFromPa said, keep that kill wire away from any 12V source.  I like the momentary push button switches myself but what ever works, use it.


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#7 RAJ OFFLINE  

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Posted February 01, 2016 - 05:05 PM

Ok, the green wire should be the kill wire? Where should I route the red wire? I would like to keep the ammeter in the loop if possible. The switch I have is a universal automotive style for a battery ignition. It has terminals for BAT, ACC, IGN and one unlabeled (starter?)

 

I have not had the cover off to look at what it has for SSI. I have very little experience with these older Tecumsehs.


Edited by RAJ, February 01, 2016 - 05:12 PM.


#8 Tecumseh power OFFLINE  

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Posted February 01, 2016 - 11:53 PM

The green wire is the kill wire, the wire from the middle plug on the rectifer goes to the light terminal on the switch, from there it charges the battery through the switch through the amp meter. The right switch will have an m for magneto. B for battery. L for lights,s for starter. And a a fith, terminal You will have to meter the switch and make sure it will work. Just make sure the switch never sends power through the m terminal to the charge coil on the stator. It has to be ground only wire your switch up like this. It's simple just don't over think it. Just make sure it grounds the magneto through the m terminal and doesn't send 12v volts through it. The older points ignition switches did. The solid state ones dont. A newer mtd mower switch is the same as what you néed, your switch should be wired so it sends power in each position the same as this picture

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Edited by Tecumseh power, February 01, 2016 - 11:58 PM.

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#9 Tecumseh power OFFLINE  

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Posted February 03, 2016 - 01:42 AM

Ok, the green wire should be the kill wire? Where should I route the red wire? I would like to keep the ammeter in the loop if possible. The switch I have is a universal automotive style for a battery ignition. It has terminals for BAT, ACC, IGN and one unlabeled (starter?)
 
I have not had the cover off to look at what it has for SSI. I have very little experience with these older Tecumsehs.

if you have any more questions pm me I can try to help sometimes it's hard for me to explain what to do. I do these tecumsehs all the time so I can help you the best I can.
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#10 Tecumseh power OFFLINE  

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Posted February 03, 2016 - 01:44 AM

Is there a 3 wire plug comming out from the blower housing?
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#11 Tecumseh power OFFLINE  

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Posted February 03, 2016 - 01:47 AM

If there is a 3 wire plug the middle one goes straught to the m on the key and the two other ones go to the outside tabs on the rectifier. The middle plug on the rectifier goes up to the key also.
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#12 RAJ OFFLINE  

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Posted February 03, 2016 - 08:33 PM

There is a two wire plug coming off of the engine. The original John Deere external regulator-rectifier is still on the tractor but  is not used because this engine has its own regulator I assume. I imaging your idea is the same with the two wires. One is the kill wire, the other for charge. I was just unsure where to route this wire in connection with the ammeter, ignition switch and battery. There are lots of diagrams but I guess I am having a hard time deciphering some of them. I am fine using a separate kill switch instead of worrying about a bad ignition switch, I just want to be sure the ammeter can be used and the battery will charge.

 

If you look closely at the picture of me holding the two wires, you can see the two wire harness coming from the engine. There is a three wire plug coming out of the blower housing but goes to the regulator then goes to the two wire plug.


Edited by RAJ, February 03, 2016 - 08:34 PM.


#13 Tecumseh power OFFLINE  

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Posted February 03, 2016 - 09:38 PM

They both go to the key, that is a 29 amp system you have if the rectifier is on the blower, the green goes to m, or your own kill switch and I'll will run up to my garage and tell you what terminal the red goes on. I think it goes on L but I'm not 100% sure I will be back
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#14 Tecumseh power OFFLINE  

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Posted February 03, 2016 - 09:46 PM

Should look the same as this 3 into 2. The red wire goes to L. Or if it is a different switch it would be marked acc.goes from there to one side of the ammeter to the lights. There is another one marked b that comes from the selinoid to the key and another marked s that goes from the key to the selinoid to excite it.

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#15 Tecumseh power OFFLINE  

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Posted February 03, 2016 - 09:48 PM

You can wire it up so all the switch does is start it if you want and have separate switch for lights kill and charge but it's alot of messing around
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